When building aircraft structures by assembling and fastening components together according to a blueprint, plan or design, it is desirable to produce a structure that is as true as possible to the design. Such assembly accuracy can improve the fit and function of the structure. Component assembly accuracy, while desirable in most applications, is necessary for proper operation of structures operating under demanding conditions. For example, a large structure such as a commercial airliner may include millions of components and fasteners, each of which should be assembled in accordance with a specific design for the aircraft to perform as intended.
Relative to the described aircraft structure assembly processes, it is important not only to ensure that all components are assembled into the aircraft structure, but also that each assembled component is in the correct position. Depending on the type of component in the aircraft, minor deviations in component position may have a significant effect in the operation of the aircraft, or may alternatively have effects that are not immediately apparent but that are nevertheless important for the efficient operation of the aircraft.
Various inspection methods for assembly completeness and correctness of aircraft structures have successfully been used in the past. One example of a known inspection method can be found in US 2012/0303336 A1, which describes an arrangement for verifying a real model by using a virtual model. Another example can be found in US 2003/0227470 A1, which describes an augmented reality system in which the registration accuracy between a virtual environment and the real environment is measured. These and other similar systems rely heavily on manual operations in which an operator is tasked with spotting and recording issues uncovered by visual inspection. However, given the customary drawbacks of manual or visual inspection, especially in assemblies involving millions of components, the current methods of inspection cannot reliably provide infallible results. Moreover, because of the size and complexity of the assemblies and the number of components, highly complex checking is required, which is a time consuming, labor-intensive and expensive operation.